Gunman at Discovery Channel HQ shot, killed by police

UPDATE: Police say the gunman who took three people hostage at the Discovery Channel network's programming has died after they shot him.

All three hostages escaped safely.

Police spent several hours negotiating with him after he burst into the suburban Washington building about 1 p.m. waving a handgun and with canisters strapped to his body.

Montgomery County Police Chief Thomas Manger says an explosive device may have detonated, and the suspect may have brought other devices into the building. He said as far as he knows, the 1,900 people who work in the building were able to get out safely.